But Griffin also said it didn't feel like he had torn his anterior cruciate ligament.

"I’m not a doctor, but I know what an ACL feels like, and it doesn’t feel like an ACL," Griffin said. "Hopefully we can have some positive, positive things that come out of the MRI. I took an X-ray, and it was a very good X-ray. I’m not too nervous, but I’ll definitely be praying during the MRI."

Later Sunday night, RG3 tweeted, "Your positive vibes and prayers worked people!!!! To God be the Glory!"

The injury occurred during the Redskins’ final drive in regulation. After Griffin scrambled downfield, he was tackled as he was going down by Haloti Ngata. Griffin’s leg was extended awkwardly on the play. He spoke at his postgame press conference as usual, but he walked slowly and limped to the podium.

Griffin showed the toughness that has endeared him to teammates after his injury. He was helped off the field, but returned after missing just one play. Throwing off one leg, stayed in the game for four more plays and completed two passes—a 15-yarder to Santana Moss and a 22-yarder to Pierre Garcon. But after his next pass was incomplete, Griffin slumped to the ground and had to be helped off again.

This time, he didn't return.

"I knew I needed to get out at that point," Griffin said. "I couldn’t move. At some point, you have to do what’s right for the team. If I would have played the rest of that game, I probably would have hurt myself even more. You gotta trust those guys, and trust yourself when you know enough is enough. When I first came out, I didn’t think enough was enough. But after being out there for a few plays, and realizing that I really couldn’t do too much, I had to get out."

It ended well for Redskins, when rookie backup Kirk Cousins completed the touchdown drive and scored on a two-point conversion that sent the game into overtime. Now with the good news on Griffin’s MRI, the Redskins will hope he can recover quickly enough to play in Week 15.

If RG3 has to miss any time, it’ll be up to Cousins to continue the Redskins' recent hot streak. They’ve won four straight in large part because of the dangers posed by Griffin—with both his arm and his legs.

With Cousins, the Redskins likely would not use a lot of the zone read game they love to use with Griffin. Cousins ran a more traditional offense in college and can run the Redskins' usual play-action game. He’s not a threat to run with the ball, so the zone read would not be as big a weapon.

Cousins has an excellent arm and moves well in the pocket. He feels pressure and will slide away from it, as he did on the 11-yard touchdown pass to Garcon in the final minute. But Cousins also has shown, in the preseason and in relief vs. Atlanta earlier this year, a willingness to take more chances with the ball.

That can result in big plays but also more turnovers (which is what happened with Cousins at Michigan State). Griffin has thrown just four interceptions this season. The players say they believe in Cousins and, based on what he did Sunday, they should. But it would be a major test for the Redskins to play a full game without the player credited for the franchise's turnaround.